fixed missing np on argsort on line 86
fixed missing np on argsort on line 86

zasdfgbnm/qutip,anubhavvardhan/qutip,cgranade/qutip,qutip/qutip,cgranade/qutip,qutip/qutip,anubhavvardhan/qutip,zasdfgbnm/qutip